Carburetors for internal combustion engines



May 22, 1962 J. 'r. w. MOSELEY 3,035,601

CARBURETORS FOR INTERNAL COMBUSTION ENGINES Filed March 17, 1958 2 Sheets-Sheet 1 AA AA.

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INVENTOR.

JAMES T.W. MOSELEY ATTORNEYS y 1952 J. T. w. MOSELEY CARBURETORS FOR INTERNAL COMBUSTION ENGINES 2 Sheets-Sheet 2 Filed March 17, 1958 yd W INVENTOR.

JAMES T.W. MOS ELEY ATTORNEYS United States Patent 3,035,601 CARBURETORS FOR INTERNAL COMBUSTION ENGINES James T. W. Moseley, Grosse Pointe Park, MiclL, assignor to Holley Carburetor Company, Van Dyke, Mich., a corporation of Michigan Filed Mar. 17, 1958, Ser. No. 721,841 8 Claims. (Cl. 137266) The present invention relates to carburetors for internal combustion engines, and more specifically to means associated with said carburetors for insuring rapid filling of the fuel bowl of the primary carburetor and for preventmg siphoning of fuel from the bowl of the primary carburetor.

Present day internal combustion engines have required various designs of carburetors in order to satisfy their respective needs. Some engines use a single stage carburetor having either a single or multiple induction passages; other engines require a two-stage carburetor havmg primary and secondary induction passages therein; While still other engines require a plurality of one or the other of these types of carburetors, or even a combination of them. All of these carburetors regardless of their specific design are identical in one respect; that is, each carburetizing system, whether it be a single stage carburetor or the secondary stage of a two-stage carburetor, has its own individual fuel bowl supplying fuel thereto. Since all of these carburetors have this basic structure they all have one major problem; that is, loss of fuel from the fuel bowl after engine shut-down and as a corollary,'prompt restoration of fuel to the fuel bowl or to the primary fuel bowl where multi-stage carburetors are employed. Loss of fuel may be due either to fuel evaporation caused by excessive heat within the engine compartment or a siphoning action occurring within the fuel delivery conduit. As a result of this reduction of available fuel within the bowl, prolonged cranking of the engine is sometimes required during starting until sufi'icient fuel can be pumped into the bowl to insure starting.

The problem of replenishing the fuel bowl to permit the engine to start becomes more acute in carburetors having primary and secondary induction passages with individual fuel bowls for them or in fuel supply systems employing a plurality of individual carburetors, because fuel is pumped to all of the fuel bowls at the same time; that is, in a two-stage carburetor for example, the fuel is pumped to the primary bowl and the secondary fuel bowl at the same time, thereby requiring twice as much time to fill the primary fuel bowl as if the fuel were pumped only to the primary bowl alone.

Accordingly, it is an object of the present invention to provide means which will eliminate excessive cranking when starting after a hot shut-down.

More specifically, it is an object of the present invention to provide means which will reduce the time required to fill the fuel bowl.

t'is a further object of the present invention to pro vide means which will automatically select and fill the primary fuel bowl first in a multi-stage carbureting system.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating preferred embodiments of the invention, wherein:

FIGURE 1 is a side elevational view of a carburetor embodying the invention.

FIGURE 2 is an enlarged sectional view of the valving mechanism of the invention.

FIGURE 3 is a view of one the elements taken substantially on the line 33, FIGURE 2.

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FIGURE 4 is a fragmentary perspective view in section illustrating another embodiment of the invention.

FIGURE 5 is another embodiment of the invention.

Referring first to FIGURE 1 there is illustrated a carburetor 10 having a throttle body portion 12 with primary and secondary induction passages 14 and 16 respectively, and throttle valves therein controlling the flow of combustible mixtures therethrough. The primary induction passage 14 is associated with a primary fuel bowl 18 and the secondary passage 16 is associated with a secondary fuel bowl 20.

In accordance with the present invention the fuel bowls 18 and 20 communicate with each other through a fuel supply conduit 22 having a pressure responsive valve 24 provided therein. Fuel is supplied to the bowls by a fuel pump, such for example as the pump indicated at P in FIGURE 4, adapted to be connected to the internal combustion engine to be driven thereby. The pump P is provided with a discharge passage 25 in which is located a valve 24a similar to the valve 24 previously described. The conduit 25 leads to an inlet fitting 26 through which the fuel flows to a chamber 28 formed in a wall of the fuel bowl 18.

As best seen in FIGURE 4, the fuel bowl 18 includes the fuel chamber 30 containing a float 32 carried by an arm 34 pivoted as indicated at 36 and resiliently urged upwardly by a compression spring 38. Fuel from the chamber 28 flows to a conduit portion 40 adapted to be controlled by a needle valve assembly comprising a tubular body having outlet ports 42 controlled by a needle valve 44 carried by the arm 34. Fuel supplied by the pump P flows through the ports 42 into the bowl until the float 32 rises to a level which moves the needle valve 44 into closing relation to the ports 42.

As best seen in FIGURE 4, the chamber 28 communicates with a passage 46 by means of which fuel can flow to the conduit 22. Obviously, without the use of the valve 24, fuel flowing through the conduit 25 into the chamber 28 will divide and flow at substantially equal rates to the bowls 18 and 20.

Referring now to FIGURES 2 and 3, there is illustrated the details of the valves 24 and 24a. The valve 24 is generally comprised of outer housing portions 48 and 59 which are coupled together by suitable means such as coacting threaded portions 52. The housing portions form a cavity 54 which contains a valve 56 and a spring 58 normally biasing the valve to the left as seen in FIGURE 2 against a coacting valve seat 60. The valve housing has passages 62 and 64 which are adapted to receive and communicate with suitable conduits such for example as branches of the conduit 22 seen in FIGURE 1.

As best seen in FIGURE 3, the valve element 56 is seen to comprise a generally cylindrical disc portion 66 provided with a plurality of circumferentially separated guiding projections or lugs 68 slidable within the housing portion 48. When moved off its seat, fluid flows past the valve and specifically, through the arcuate openings 79.

Referring now to FIGURE 5 there is illustrated the invention applied to a series of progressively operated carburetors. In this embodiment of the invention there is shown a primary carburetor 72 and additional sequentially acting carburetors 74 and 76. Fuel is supplied from the fuel pump such as the pump P through a check valve 24a and conduit 78 to a fuel bowl 8% of the primary carburetor. The conduit 78 connects to conduits 82 and 84 each of which is provided with a valve 24, the conduit 82 leading to the fuel bowl 86 of the carburetor 74- and the conduit 84 leading to the fuel bowl 88 of the carburetor 76.

Operation As was previously stated, the problem is one of reduc ing or eliminating prolonged engine crwking during starting due to a loss of fuel from the fuel bowl after engine shut-down. Basically, this problem can be solved by one or both of two methods; that is, by diminishing the amount of fuel lost during shut-down, and by increasing the rate of fuel delivery to the primary fuel bowl when it is associated with a secondary or additional fuel bowls. The application of this invention will result in one or both of these methods being employed.

Referring first to FIGURE 4 it will be observed that the outlet ports 42 are substantially below the normal surface of fuel within the bowl 18 when engine shut-down occurred. At this time, a column of fuel is present within the conduit 25 leading to the fuel bowl from the pump P. When the pump stops incidental to stopping of the engine, the column of fuel in the conduit 25 initiates a siphoning action which if continued will siphon the fuel from the chamber 30 to the level of the ports 42.

By providing the check valve 24a in the conduit 25, back siphoning of fuel from the fuel bowl is prevented. The valve member 56 is retained on its seat by the spring 58 and the spring is of course selected to have an effectiveness such that the valve opens at a fuel pressure substantially below that supplied by the pump P. Siphoning however occurs in such a way as to cause a flow from right to left as seen in FIGURE 2, so that the pressure developed by the siphoning flow assists the spring 58 and will retain the check valve 56 in closed position.

While the foregoing tends to reduce prolonged engine cranking by eliminating one source of fuel loss from the fuel bowl, there may be a loss due to evaporation or percolation so that additional fuel must be supplied to the fuel bowl of the primary carburetor before the engine can start. The provision of the valve 24 in the conduit 22 or in the conduits 82 and 84 as seen in FIGURE 5, is intended to accomplish this purpose. When fuel flows into the chamber 28 as seen in FIGURE 4, the valve 24 is closed by a light spring pressure which is suiiicient to maintain the valve closed so long as the fuel is permitted to flow through the ports 42 into the chamber 30 of the primary fuel bowl 18. As soon as the fuel in this chamber reaches a predetermined level the needle valve 44 rises and prevents flow through the ports 42. At this time pressure in the chamber 28 builds up toward the discharge pressure of the pump P and at some value appreciably below the outlet pressure of the pump P, the valve 56 is forced off its seat against the spring 58 and fluid flows through the other branch of the conduit 22 to the fuel bowl 2t).

Referring now to FIGURE it will be observed that a similar arrangement is provided except that the primary carburetor 72 is associated with a plurality of additional carburetors and hence fuel supplied from the pump P flows to the bowl 8d of the primary carburetor 72 until such a time as it is filled and further flow thereto is prevented by closure of its needle valve. Thereafter, the flow through the conduit 73 may divide through the conduits 32 and 84 to fill fuel bowls 36 and 88 simultaneously. Alternatively, if desired, the springs in the two valves 24 shown in FIGURE 5 may be of slightly different efiectiveness so that a selected one of the fuel bowls 86 and 83 fills completely before fuel is delivered to the other fuel bowl.

Since the foregoing constructions provide for delivery of the entire output of the fuel pump P to the fuel bowl of the primary carburetor, it is apparent that this fuel bowl can be filled or brought to an operating level in a fraction of the time that would otherwise be required.

The drawings and the foregoing specification constitute a description of the improved carburetors for internal combustion engines in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

l. A carburetion system for an internal combustion engine comprising a primary carburetor having a fuel bowl, a secondary carburetor having a fuel bowl, a fuel pump adapted to be connected to the engine, a fuel delivery passage connected to said pump, a primary branch passage leading from said delivery passage to the fuel bowl of said primary carburetor, a secondary branch passage leading from said delivery passage to the fuel bowl of said secondary carburetor, normally closed valve means in said secondary branch passage, and yieldable means providing for opening of said valve means at a pressure less than the delivery pressure of said pump.

2. A carburetion system for an internal combustion engine comprising a primary carburetor having a fuel bowl, a secondary carburetor having a fuel bowl, :1 fuel pump adapted to be connected to the engine, a fuel delivery passage connected to said pump, a primary ranch passage leading from said delivery passage to the fuel bowl of said primary carburetor, a secondary branch passage leading from said delivery passage to the fuel bowl of said secondary carburetor, normally closed valve means in said secondary branch passage, said valve means comprising a valve seat facing said secondary carburetor, a valve member movable onto and off of said seat to closed and open position, and spring means urging said valve to closed position, said spring being yieldable when said valve member is subjected to fluid pressure at the pump side thereof of a value less than delivery pressure of said pump.

3. A carburetion system for an internal combustion engine comprising a primary carburetor having a fuel bowl, a secondary carburetor having a fuel bowl, a fuel pump adapted to be connected to the engine, a fuel delivery passage connected to said pump, a primary branch passage leading from said delivery passage to the fuel bowl of said primary carburetor, a secondary branch passage leading from said delivery passage to the. fuel bowl of said secondary carburetor, a float valve in said primary branch operable to close said branch when said bowl of said primary carburetor is full, normally closed valve means in said secondary branch passage, and yieldable means providing for opening of said valve means at a pressure less than the delivery pressure of said pump.

4. A carburetion system for an internal combustion engine comprising a primary carburetor having a fuel bowl, a plurality of additional sequentially operable carburetors, a fuel pump adapted to be connected to the engine, a fuel delivery passage connected to said pump, a primary branch passage leading from said delivery passage to the fuel bowl of said primary carburetor, additional branch passages leading from said delivery passage to the bowls of said additional carburetors, and normally closed valves in said additional passages to insure delivery of all fuel to the bowl of said primary carburetor and movable to open position when subjected to a fluid pressure less than delivery pressure of said pump to cause fuel to flow to the bowl of said additional carburetors after the bowl if said primary carburetor is fdled.

5. A carburetion system for an internal combustion engine comprising a primary carburetor having a fuel bowl, a plurality of additional sequentially operable carburetors, a fuel pump adapted to be connected tbathe engine, a fuel delivery passage connected to said pump, a primary branch passage leading from said delivery passage to the fuel bowl of said primary carburetor, additional branch passages leading from said delivery passage to the bowls of said additional carburetors, normally closed valves in said additional passages to insure delivery of all fuel to the bowl of said primary carburetor and movable to open position when subjected to a fluid pressure less than delivery pressure of said pump to cause fuel to flow to the bowl of said additional carburetors after the bowl of said primary carburetor is filled, and yieldable means associated with said normally closed valves, said yieldable means being of different effectiveness to provide for predetermined sequential operation thereof.

6. A carburetor system for an internal combustion engine comprising a primary carburetor having a fuel bowl, a secondary carburetor having a fuel bowl, a fuel pump located below the level of the fuel bowl of the primary carburetor and adapted to be connected to the engine, a fuel delivery passage connected to said pump, a check valve in said passage disposed to prevent return flow of fuel to said pump, a primary branch passage leading from said delivery passage to the fuel bowl of said primary carburetor, a secondary branch passage leading from said delivery passage to the fuel bowl of said secondary carburetor, normally closed valve means in said secondary branch passage, and yieldable means providing for opening of said valve means at a pressure less than the delivery pressure of said pump.

7. A carburetor system for an internal combustion engine comprising a primary carburetor having a fuel bowl, a secondary carburetor having a fuel bowl, a fuel pump adapted to be connected to the engine, a primary fuel delivery means connecting said pump to the fuel bowl of said primary carburetor, means restricting flow of fuel into the fuel bowl of said primary carburetor, a secondary branch passage leading from said primary fuel delivery means to the fuel bowl of said secondary carburetor, normally closed valve means in said secondary branch passage, and yieldable means providing for opening of said valve means at a pressure less than the delivery pressure of said pumpv 8. A carburetion system for an internal combustion engine comprising a primary carburetor having a fuel bowl, primary fuel supply means including a chamber, a valved passage connecting said chamber to the interior of said fuel bowl and constituting a restriction to free flow of fuel from said chamber into said fuel bowl, a fuel pump adapted to be connected to the engine and a fuel delivery passage connecting said pump to said chamber, a secondary carburetor having a fuel bowl, secondary fuel supply means including a branch passage connecting said primary fuel supply means to the fuel bowl of said secondary carburetor, normally closed valve means in said branch passage, and yieldable means adapted to maintain said valve means closed while fuel is permitted to flow into the fuel bowl of said primary carburetor, said yieldable means providing for opening of said valve means at a pressure substantially less than the delivery pressure of said pump.

References Zited in the file of this patent UNITED STATES PATENTS 1,642,332 Carlsson Sept. 3, 1927 1,655,902 Griffon Jan. 10, 1928 2,293,884 Boyce Aug. 25, 1942 2,713,854 Conover July 26, 1955 2,811,862 Libby Nov. 5, 1957 

